radvd: update to latest stable version

package/radvd/patches/patch-configure_ac

@@ -1,10 +0,0 @@
---- radvd-2.5.orig/configure.ac	2014-08-04 02:23:05.000000000 +0200
-+++ radvd-2.5/configure.ac	2014-08-12 08:44:04.000000000 +0200
-@@ -157,7 +157,6 @@ AC_CHECK_HEADERS( \
- 	net/if_types.h \
- 	sys/param.h \
- 	sys/sockio.h \
--	sys/sysctl.h \
- 	sys/time.h \
- 	time.h \
- )